I have listened to the MF2500A on many occasions and its
a nice amp. The A revsion is quieter with better detail
and is more transparent over the previous 2500. It's still
very musical as you would expect with a CJ. I have not
heard the 2250 but I don't think you could go wrong with
either. I would lean towards the 2500A simply because it
has all the latest updates and a bit more power if you need
it.
Good luck
Cmach